PROJECT SUMMARY Because of its close phylogenetic relationship to the human, the non-human primate (NHP) brain holds enormous potential for understanding structure, function, development and pathology of the human brain. However, many obstacles impede studies of NHPs, among these, significant logistic, ethical, and financial burdens. The Department of Neuroscience at Yale houses a unique collection of brain tissue from NHP macaques, ranging in age from embryonic to adult, which was generated over four decades, in the laboratories of Dr. Pasko Rakic and the late Dr. Patricia Goldman-Rakic. The collection includes four Case Sets of slides: (1) [3H]thymidine-labeled serially cut brains for cell birth dating, (2) brains labeled with tritiated amino acids for tract tracing, (3) brains from monkeys with enucleations and selected cortical lesions, (4) and brains from prenatally X-irradiated and ultrasound-exposed monkeys sacrificed postnatally. A 5th Case Set is comprised of EM blocks from multiple brain regions of fetal and postnatal monkeys. The objective of this grant is to make this unique collection an international research resource (MacBrainResource) that is readily available to the neuroscience community at-large. To accomplish this, we propose (1) to inventory and catalogue the collection, (2) to restore the slides to optimal condition by re-coverslipping and in some instances re-staining them, (3) to publicize the resource via mailings, presentations at the Society for Neuroscience meetings and our website (MacBrainResource.org), and (4) to facilitate use of MacBrainResource by outside investigators both on site and remotely by transmission of high resolution images via the internet. The value of the MacBrainResource collection is immeasurable. Primate brain research not only requires animal sacrifice but is very expensive. Making existing NHP brain tissue available will avoid costly duplication of experiments and unnecessary sacrifice of animals. With increasing pressure to find alternatives to primate research, establishment of the MacBrainResource would allow researchers worldwide to conduct primate studies without the need to sacrifice a single new animal. Proof that this resource represents a viable and valuable alternative for de novo primate research comes from the publication of several recent papers that utilized this material (e.g. Duque at al., 2011; 2015; 2016; Ratnanather et al. 2013; Selemon et al., 2013) as well as demand for material from investigators all over that world. Dedicated personnel, proper cataloguing, and adequate equipment would ensure that these slides and EM blocks are preserved for future generations of neuroscientists to exploit, perhaps using methods not yet developed.